中英文文献翻译—运动型7速双离合器变速器系统

2021年1月26日发(作者：女服务员的英文)

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外文文献原文


7-Speed Dual Clutch Transmission System for Sporty Application
ABSTRACT:
With
its
7-speed
dual
clutch
transmission,
ZF
has
introduced
an
innovative transmission for sporty applications. The close ratios combined with extremely
spontaneous
drive
behavior
makes
it
an
ideal
transmission
for
sporty
applications.
This
article describes the compact gear set with lubrication by injection for improving the level
of efficiency and increasing the engine-speed-strength, the dual clutch unit as well as the
hydraulic
control
unit,
which
is
based
on
the
pre-control
principle,
are
also
described
in
detail. The hy-draulic control principle provides the option of a hydraulic cruise mode in
the
event
of
an
electronics
failure.
In
addition
to
the
transmission
design,
functional
features that also highlight the sporty character of the transmission are described in detail.

Key words:
Automatic transmission; Dual clutch; Vehicle connection; Efficiency
1 Introduction
When it comes to the field of automatic transmissions, dual clutch systems currently
represent the benchmark in terms of spontaneity and sportiness. In this type of transmission,
which is based on a countershaft transmission, these advantages are combined with a very
direct
The
7-speed
dual
clutch
transmission
for
the
standard
driveline
presented
here
is
designed for a torque capacity of up to 520 Nm and rotational speeds of up to 9250 rpms.
In order to be able to achieve these performance data in the existing installation space, a
concept was developed in which an oil chamber as well as lubrication by injection are used.
Before
introducing
the
transmission
′
s
several
unique
features
in
more
detail
below,
an
overview
of
the
basic
transmission
design
will be
presented,
Fig.

engine
torque
is
introduced
to
the
dual
clutch
via
a
torsion
damper
(not
shown
in
Fig.
1).
The
multidisk
clutches in the dual clutch are radially nested in one another and transfer the torque to both
input shafts
in
the countershaft transmission gear set.
In this
case, due to the installation
space,
the
countershaft
is
not
located
under
the
main
shaft,
but
is
tilted
laterally.
This
becomes possible because the concept is based on lubrication by injection with a dry sump.


On the one hand, lubrication by injection improves heat removal, on the other, there are no
noticeable
losses
due
to
the
gears
splashing
in
the
oil
pan.
The
oil
is
supplied
to
the
transmission via an internal gear pump which is driven by a spur gear train behind the dual
clutch. With the help of a spur gear train, the drive unit has the advantage that, via different
gear ratio phases and depending on the intended use, the flow rate and the max. speed of
the pump can be adapted. An additional advantage is that based on theresulting
I proved
installation space, an optimal ratio between the pump width and the pump diameter can be
achieved for the pump
′
s level of efficiency. The hydraulic control unit is arranged under
the
gear
set.
The
hydraulic
unit
supplies
the
clutch,
based
on
need,
with
pressure
and
cooling oil as well as shift actuators. The latter are arranged laterally to
the gear set and
work with double- acting cylinders. The sensor for detecting the position of the gearshifts is
attached directly onto the four gearshifts. The transmission has an external control unit.

Fig.1

Overview dual clutch transmission (DCT)
2 Seven speeds with sophisticated stepping-a concept for extrme sporti- ness

The gear set concept of the dual clutch transmission introduced here was developed in
house taking into consideration the following requirements:
High power density
High speed endurance strength up to 9250 rpm Variability and modular design
Representation of transmission-ratio spreads of about 4.7 and 6.8 with 7 speeds
Use of existing synergies for manual transmissions
After extensive systematic development of the
gear set in which many thousands of
variants were produced and compared, the gear set concept that is illustrated in Fig. 2 is the
final variant and the ideal concept for achieving the goals specified.
The
gear
set
selected
is
based
on
the
constant
drive
concept
and
consists
of
two
concentric drive shafts each of which are driven by one of the two multidisk clutches in the



Fig.2

Gear set scheme of 7D variant
dual clutch, two countershafts also concentric to one another, a main shaft and an output
shaft. The gear ratios are engaged by the four synchronizer units A/B, C/D, E/F, and G/H,
which
are
arranged
on
the
main
shaft
and
on
the
hollow
countershaft
and
these
are
connected to the loose wheels or the adjacent shafts. An important feature in the gear set is
the connectability of both countershafts through the C/D synchronizer unit. In the D shift
position, the gear ratios selected in this way can be doubly used which reduces construction
costs compared to conventional dual clutch gear sets. Similarly, this feature is used in first
gear because then the vehicle is started up using the more powerful K1 clutch. Because of
this
dual
use
of
the
last
gear
level
in
the
transmission
for
the
first
and
second
gear,
the
desired
ratio
step
1-2
is
achieved
through
the
transmission
ratios
of
both
constant
drive
phases.
The use of the K1 clutch for starting up in first gear results inevitably in the direct gear
also being assigned to the odd subsection. In this case, the fifth and seventh gears can be
selected as a direct drive. With this feature, it was possible to develop a modular gear set
which, on just a few changes,contains two different
transmission gear ratio variants
with
fundamentally different characters.
For the first version, with an overall spread of about 4 . 7 , the seventh gear is selected
as a direct gear (called the 7D variant). Fig. 2 shows the relevant gear set diagram with the
performance
flows
in
all
speeds.
Due
to
its
sophisticated
gear
steps,
this
transmission
is
highly suitable for very sporty vehicles that need only a
to
the
high
rotating
engine.
Optimal
tractive
power
can
be
provided
at
any
time
during


vehicle operation.
The second version is based on the 7D variant, however, fifth gear was selected as the
direct
drive.
When
maintaining
the
torque
multiplication
ratio
and
in
adapting
the
transmission ratio of several lower gear levels, you get the 5D variant with a considerably
higher
transmission- ratio
spread
for
vehicles
with
increased
comfort
demands
and
simultaneously reduced consumption.
Fig.
3
illustrates
the
design
of
the
7D
variant.
The
main
similarity
with
existing
manual transmissions for standard transmissions is noticeable. Due to the compact gear set
design, the sufficient shaft dimensioning and the favorable arrangement in proximity of the
bearing of the high transmitting ratios, central bearing glasses were not necessary despite
the
proportionally
large
bearing
l,
only
two
housing
bearing
levels
are
necessary where the front level is located behind both constant gears. In addition, a very
compact and inexpensive transmission design could be implemented based on the bearing
concept selected, especially in the area of the hollow shaft.

Fig.3

Sectional Drawing of 7D variant
3 The dual clutch
The central module of this highly topical transmission concept is the wet dual clutch.
With a broad spectrum of technical features, it implements the functional provisions of the
transmission control unit and thus distinguishes the special character of this transmission
concept.
Very fast
delay times, low inertia
and
good, comfortable
friction
value progressions
facilitate, very sporty handling with highly dynamic gear shifting and comfortable cruising
at
a
high
level
of
efficiency.
The
dual
clutch
placed
directly
on
the
transmission
input
accepts the engine torque from thtorsion damper and feeds it to one of the two subsections,
depending on the situation.
Safety considerations have led to a